This invention relates to a curling machine provided with an adjusting device for winding evenly elongated workpieces into spirals.
The improvement can be particularly embodied to a machine having a vertical axis curling mandrel and a horizontal axis twisting mandrel that is yet disclosed in the Italian patent application No. RM2001A000552 by the same inventor. However, in the same way, the improvement could relate to only a curling machine.
Referring to FIG. 1 a combined machine for curling strips and twisting polygonal cross-section elongated workpieces, which is the subject-matter of the above mentioned patent application No. RM2001A000552 by the same inventor, is generally therein shown. This combined machine comprises a machine frame denoted as 1, sustaining an upper horizontal worktable 2. A vertical axis curling mandrel 3, designed to hold a curling tool 4, passes through the upper worktable 2. The curling tool 4 is comprised of a plurality of subsequent articulated links for bending a metal strip. The curling tool 4 is known from the Italian patent No. 1.302.352 by the same inventor. Further, on the same worktable 2 provision is made of a known lever-controlled supporting or counteracting element 20 for the metal strip in order to allow the metal strip to be buckled. A horizontal-axis chuck 7, which is provided with locking jaws for the one end of a workpiece to be twisted (such jaws are not shown in detail in the drawings, as known) is mounted in a not fixed way to a hollow twisting mandrel projecting from a front wall 5. A supporting bar 8, which is sustained by a pedestal 9 at its end, carries a vice 10 adapted to lock the other end of the generally polygonal cross-section workpiece to be twisted. An electric motor 11 through a suitable transmission, is mounted inside the frame 1 to move in turn both the curling mandrel and the twisting mandrel.
In operation, an elongated workpiece, such as a metal strip or other workpiece to be curled or bent into a spiral, is retained by the curling tool 4 which is connected to the vertical-axis mandrel. On the upper horizontal worktable 2 of the machine the supporting or counteracting element, in general a spring-charged pin (in case, carrying an idle roller) having a vertical axis movable along a slot of the horizontal worktable, is controlled by an operator through a hand-lever. The supporting or counteracting element acts as a sliding abutment for the elongated workpiece, which, otherwise, would only rotate around the bending mandrel, that retains the workpiece, and would not buckle.
The operation of the counteracting element and its function of co-operation with the curling mandrel for the deformation of the elongated workpiece are automatic. However, the force applied by the spring-charged pin onto the elongated workpiece, is not adjustable, since said force is merely produced by the lying and the shape of the slot along which the pin is moved. Further, such a force is susceptible to change in consequence of the progressive wear of the slot. Therefore, a machining reproducibility is not assured in the course of time.